Stretching machines



Dec. 13, 1955 HAASE 2,726,562

STRETCHING MACHINES Filed Aug. 13, 1951 5 Sheets-Sheet 3 INVENTOR fliizlime,

ATT( )RNEY Dec. 13, 1955 F. HAASE 2,726,562

\ STRETCHING MACHINES Filed Aug. 15, 1951 5 Sheets-Sheet 4 ATTORNEY Dec.13, 1955 F. HAASE 2,726,562

STRETCHING MACHINES Fil 15, 1951 5 Sheets-Sheet 5 INVENTOR. FRITZ HAASEBY W, ania/7, MW

ATTOZ/VEKS:

STRETCHING MACHINES Fritz Haase, Goppingen (Wurttemberg), Germany,assignor, by mesne assignments, to Tube Reducing Corporation,Wallington, N. J., a corporation of Delaware Application August 13,1951, Serial No. 241,635

9 Claims. (Cl. 8019) This invention relates to a stretching machine forreducing the wall thickness of metal.

The invention further relates to a stretching machine for producingwedge-shaped strips or bands or other articles of like nature.

The invention further relates to a stretching machine in which astretching tool cooperates with a counter-tool to reduce the thicknessof metal fed into a gap therebetween, in combination with means forvarying the gap; a machine having a stretching tool and counter-tool incombination with means for feeding metal thereto whose feeding rates areadjusted to the variations of the gap and/or the then existing reductionrates of the metal.

The invention further relates to a machine in which a roll segmentrotatably mounted on a reciprocating slide cooperates with acounter-tool to reduce the thickness of metal fed into a gaptherebetween, in combination with means for varying the gap; specificmeans for enlarging the gap during the return stroke of the rollsegment; specific means for varying the gap after each full stroke ofthe roll segment or after a series of strokes, the gap being varied inequal or unequal amounts; a machine in which the roll segment cooperateswith a counter-tool in combination with means for feeding metal theretowhose feeding rates are adjusted to the variations of the gap, and/ormeans for varying the gap.

The invention further relates to a stretching machine for reducing thewall thickness of articles of rectangular cross section in whichsections of the article are increment by increment advanced on a plane,which forms an angle with the stretching plane, and subsequently spreadout .by a reciprocating tool whereby the wall thickness of the articleis reduced.

One of the main features of the invention resides in the provision of aroll segment rotatably mounted on and supported on its entire lengthagainst a slide which can be reciprocated by any suitable means, and acountertool provided with the feeding and stretching plane. The rollsegment when reciprocated by the slide is unrolling on the counter-toolthereby reducing the wall thickness of the section of the articleadvanced on the counter-tool.

Prior to the present invention, a reciprocating prismatic tool guided ina press frame has been used, but this has the disadvantage of heavyfriction strain exerted by and on the tool. Since in the stretchingmethod very high reduction rates-in excess of 80 per centare normallyused, the friction strain on and by merely sliding tools is particularlyhigh and when dealing with the stretching of. steel, requires the use ofphosphate coating to prevent direct contact between the tool and themetallic surface of the article to be stretched.

When using rolls as stretching tools there is the drawback that they aresubjected to heavy strains of flexure, particularly in dealing with theproduction of bands of great width. As the stretching machine accordingto the invention is chiefly used for the production of wedge- .shapedstrips, crowned rolls as they are used in conven nited States Patent 92,726,562 Patented Dec. 13, 1955 great differences in the reductionrates, the strains of fiexure vary within great limits.

When using a roll segment mounted on and supported on its entire lengthagainst a reciprocating slide, on the one hand the heavy strains offriction of the merely sliding prismatical tool are avoided, and on theother hand the roll segment can be supported against the slide, and theslide against the rigidly built press frame so that practically noflexure of the roll segment takes place even if strips of large widthare worked. 7

As during the return stroke of the roll segment an additional if smallreduction would take place resulting in strains of fiexure manifestingthemselves in the section of articie between the roll segment and thefeeding apparatus, a further feature of the invention resides in theprovision of devices adapted to enlarge the gap between the roll segmentand the counter-tool during the return stroke of the roll segment sothat the latter unrolls without pressure on the section of the articlereduced in the foregoing forward stroke.

As for the production of wedge-shaped strips the gap between the rollsegment and counter-tool has to be enlarged or diminished after eachfull stroke of the roll segment, a further feature of the inventionconsists in the provision of devices adapted to enlarge or to diminishthe gap between the roll segment and the counter-tool after each fullstroke or a series of full strokes. Such devices are advantageouslycombined with those provided for the enlarging of the gap during thereturn stroke of the roll segment. I

Wedge-shaped strips or sheets cannot be produced in endless lengths likeconventional strips and sheets of uniform wall thickness. Tapered stripsor sheets as used in aircraft industry must have not only the desiredtaper but also the exact lengths. This requires a careful planning ofthe stretching operation. The only practical way to produce any exacttaper and length of a tapered strip or sheet is to keep the lengths ofstretched sections invariable. This may be illustrated by the followingexample:

A wedge-shaped strip is to be produced out of a band having a wallthickness of 5 mms. Such tapered strip shall have a length of 5 metersand is to be 1 mm. thick at the one end, 5 mms. thick at the other end.The stretched section shall have a length of 10 mms. 500 revolutionsofthe crank will then be necessary to produce the tapered strip of 5meters length. Beginning with highest reduction rates the band is to beadvanced by 2 mms. After the first stretching operation the gap isenlarged by 4 -DOS mm.

As is to be easily understood, when keeping the feeding ratesinvariable, already the length of the second stretched section wouldturn smaller by about .08 mm. and the following sections would turnsmaller and smaller, the last section having a wall thickness of and alength of 2 mms.

The thus produced wedge-shaped strip or sheet would have neither therequired taper nor the required length. In order to obtain taperedstrips and sheets having not only the desired taper but also the exactlength, according to the invention, devices are provided by means ofwhich the feeding rates are automatically adjusted to the then existingreduction rates; for instance when dealing with the production of stripsof increasing wall thickness such devices are to gradually enlarge thefeeding rates so that the length of the stretched sections remain equalmms. =5 mms.

through the whole length of the wedge-shaped article.

Other objects and features of our invention will become apparent from areading of the following specification in the light of the accompanyingdrawings, in which Fig. 1 is a front elevation of the apparatus seenfrom the side where the article to be stretched is introduced;

Figure 2 is a sectional view in line AA of Fig. 1;

Figure 3 is a front elevation of the stretching machine seen from theside where the finished article leaves the machine, the right half ofthe figure showing a sectional view in line BB of Fig. 4;

Figure 4 is a side elevation of the machine seen from the side where thegap regulating devices are arranged;

Figure 5 is a sectional view in line CC of Fig. 3;

Figure 6 shows details of the devices for lifting the upper feedingroll;

Figure 7 is a sectional view in line DD of Fig. 4;

Figure 8 is a sectional view in line EE of Fig. 7;

Figure 9 is a sectional view in line FF of Fig. 7;

Figure 10 is a sectional view in line GG of Fig. 1;

Figure 11 is a sectional view in line HH of Fig. 1;

Fig. 12 shows a schematic assembly of the devices for automaticallyvarying the feed rates;

Fig. 13 demonstrates the various timing and relationship of the cams inoperation.

Mounted in the press frame 1 the intermediate shaft 2 drives a crankshaft 5 by means of pairs of toothed wheels 3, 4 and 3', 4'. Thefork-shaped connecting rods 6 and 6 are linked to the toggle-levers 8,8a and 8', 8a by means of the journals 7, 7'. The toggle-lever arms 8and 8' are supported against the press frame by means of the journals 9and 9'. The toggle-lever arms 8a and 8a are connected with the slide 12by means of the journal 10 which slide is reciprocated by the crankdrive through the intermediary of the toggle-levers 8, 8a and and 8',8a. The slide 12 and the journal 10 are suspended on the press frame bylateral guiding plates 11 and 11' (Fig. 3). The roll segment 14 islinked (Fig. 3) to the journal 10 by means of the lateral guide plates13, 13'. As is to be seen from Fig. 5 the guide plates 13, 13' aregeared with the racks 15, 15 which, at their ends, are held inadjustable proper positions by screws and springs. This device isnecessary to hold the roll segment 14 in its proper working position.

The counter-tool 16 rests on the spindles 17, 17 which can be lifted andlowered by rotating the respective cylinder nuts 18, 18' and is providedwith a feeding plane which forms an angle with the stretching plane.This angle which may be varied within broad limits has a twofoldpurpose. plane as the stretching plane, it would not be possible toadvance the work piece. The second point is that the deformation of thework piece is considerably facilitated due to the fact that by arrangingthe feeding surface at an angle to the stretching surface the greaterpart of the increment to be stretched lies beyond the plane formed bythe surface of the finished work piece, the result of which is thatstretching consists mainly in pushing such greater part of the incrementin the direction in which the stretching takes place and that suchcomponent of deformation as tends to press the increment on thecountertool is very small compared with other metal forming processes. p

In order to lower the counter-tool during the return stroke and to liftit again after the return stroke is finished as well as to vary the gapbetween the roll segment and the counter-tool after each full stroke,the following devices are used.

To the toothed wheel 4 (Fig. 4) a grooved cam 19 is secured in which theroll 20 mounted to the end of the bell-crank 21 is guided. Thisbell-crank is rotatably mounted on a journal in the press frame and withits shorter arm linked to the head piece 22. Rotatably mounted in thehead piece (Fig. 7) is the regulating spindle 23 which is screwed in thehollow rack 24. This With a feeding plane lying in the same connectedwith the lever 22c. strokeof the head piece 22 the free wheel clutches22d rack is held in engagement with the toothed wheel 25 mounted on theshaft 26 by means of the supporting pulley 24a and the guiding disks 25aand 25b.

On shaft 26 are mounted the worms 27, 27' which are in engagement withthe worm wheels 28, 28' secured to the cylinder nuts 18, 18'.

By means of the above described devices the countertool is lifted orlowered only temporarily within a part of the full stroke but there isno change of the gap between the roll segment and the counter-toolbetween one full stroke and the next full stroke. When dealing with theproduction of wedge-shaped articles which requires increasing ordiminishing the gap after each full stroke the following additionaldevices may be combined with the above described ones, such devicesbeing shown in an enlarged scale in Figs. 7 to 9.

Rotatably mounted in the head piece 22 is a worm 22a which is inengagement with a worm wheel secured to the upper end of the regulatingspindle 23. An extension of the worm 22a carries the fixed box 22b onwhich the lever 22c is rotatably mounted. In order to couple the lever22c with the worm 22a, freewheel clutches 22d and 22d are provided themotions of rotation of which free wheel clutches being opposite to eachother. The inner races 22c, 22c of the free wheel clutches are rigidlymounted on box 22b whilst the outer races 22], 22 are provided with afine gearing 22g. A clamping piece 22h correspondingly geared andslidably mounted on the lever 22c can be clamped to one or bothfree-wheel clutches by means of the screw 22i whereby the outer race ofthe respective free-wheel clutch is coupled with the lever 220. Thejoint piece 22l is rotatably mounted on a box 22k adapted to be slidwithin a slot of lever 22c. The screw 22m serves to fix the box 22ksimultaneously in the slot of the lever 22c and that of the curved piece22n mounted on the press frame.

The above described device operates as follows:

When the toothed wheel 4 turns in clockwise direction the vertical armof the lever 21 is moved to the left thereby pushing down the head piece22, spindle 23, and rack 24. The thus caused rotation of the toothedwheel 25 is transmitted to the shaft 26 and the worms 27, 27 which causethe worm wheels 28, 28' and the cylinder nuts 18, 18 to rotate. Shapeand arrangement of the cam 19 on the toothed wheel and motion ofrotation of the worms and worm wheels are chosen so that in thebeginning of the return stroke of the roll segment the counter-tool islowered by a small amount and towards the end of the return stroke islifted either into its previous position or into any new positioncorresponding to the desired change of the gap. To the latter purposethe above described additional gap regulating devices have to be set towork.

When dealing with the production of articles which as a whole are to bereduced uniformly in wall thickness, or in certain sections of them, thelever 220 is put into its zero position, as shown in Fig. 4 by dottedlines, or the coupling of the free wheel clutches 22d and 22d with thelever 220 should be loosened. No rotation is then imparted to theregulating spindle 23. In the beginning of the return stroke thecounter-tool is lowered by a small amount, and, toward the end of thereturn stroke, is lifted to its previous position. When, however, thelever 22c is turnedvfrom its zero position in anticlockwise directionand fixed in the slot of the lever 22c and that of the curved piece 22!:in any position between the zero position and the position shown in Fig.4, any downward movement of the head piece results in a rotation of theworm 22a, and as the worm 22a is in engagement with the worm wheelsecured to the upper end of the regulating spindle 23, a rotation isimparted to the latter which causes the rack 24 to be lifted or lowereddepending on which of the two free wheel clutches 22d and 22d As duringthe return and 22a" respectively prevent the regulating spindle 23 frombeing rotated in the reverse direction, the increase or decrease of thegap is preserved for the following forward stroke of the roll segment14. I

On the crankshaft is mounted the cam 31 (Fig. 1 and Fig. which, throughthe roll' 31a, controls the joint head 31d mounted by means of the jointpiece 31b on the bearing 310 of the press frame 1. To the joint head 31dis secured the push rod 31e which, guided in an eye of the press frame,is linked to the free-wheel clutch 32 by means of the part 31]. Thepressure spring 31g being effective between joint head 31d and pressframe 1 pushes the roll 31a against the cam 31 as far as it is permittedby the cam 47 yet to be described. Cam 31 is shaped so that the push rod312 is pushed forward while the roll segment is in its posterior deadpoint position thereby imparting a motion of rotation to shaft 34 by theintermediary of free-wheel clutch 32 and the clawcoupling 33 which shaftis in engagement with the shaft 34 by the intermediary of the pair ofgears 35, 35'. The shafts 34, 34' are connected with the feeding rolls37, 37 by the jointed couplings 36, 36'. The roll pressure necessary forfeeding is effected by the bolts screwed in the bearings 38, 39, andpressure springs 42 being effective between the bearings 38', 39 and thenuts 41 (Fig. 6). In order to introduce the article to be stretchedbetween the feeding rolls, levers 43 are provided which impart a motionof rotation to eccentrics 44 thereby lifting the feeding roll 37 by theintermediary of the cross-rail 45 and the bolts 40.

The gradual changes of the feeding rates are controlled by cam 46secured to shaft 5 (Fig. 1 and Fig. 11) and cam 47. The cam 46 is inconstant contact with the roll 46a arranged in the adjusting head 46b(Fig. 11)

which on its part is pivotally mounted on the bearing 460 of the pressframe. Horizontally arranged in the adjusting head 46b is the spindle46d by means of which the slide 462 can be moved to the left. or to theright. Pivoted in the slide 46a is the one end of the push rod 46 Whilstthe other end thereof is rotatably mounted on the lever-like extension46g of the outer race of the free wheel clutch 46h. By means of the drawspring. 46i the roll 46122 is pressed on the cam 46. The cam 47 issecured to the inner race of the free wheel clutch 46h which race ispivoted on the press frame. The push rod 48 guided in an eye of thepress frame 1 is controlled by the roll 48a.

The above described devices operate as follows:

The feeding is actuated in the posterior dead point position of the rollsegment by .thecam 31 by the intermediary of the push rod 312, thefree-wheel 32 and the claw coupling 33. i

As described above, the roll 31:: is pushed toward the cam 31 by thepressure spring 31g but only as far as it is permitted by the cam 47which defines the distance between the cam 31 and the roll 31a by theintermediary of the roll 48a mounted on one end of the push rod 48; theother end of the push rod is linked to the outer race of the free wheelclutch 32. The greater the distance between the cam 31 and the roll 31a,the smaller is the angle of rotation imparted by the cam 31 to the outerrace of the free wheel clutch 32 by the intermediary of roll 31a, pushrod 31a and part 31]. When the cam 47 is rotated, the distance betweenthe roll 31a and the cam 31 will be increased or decreased resulting ina decrease or increase of the angle of rotation of the free wheel clutch32, which angle of rotation defines the feeding rate.

The intermittent rotation of the cam 47 is effected by the cam 46 whichimparts an impulse of rotation to the lever-like extension 46g of theouter race of the free wheel clutch 46h by the intermediary of the roll46a, adjusting head 46b, and push rod 46 By each impulse of rotationimparted to the lever-like extension 46g of the free wheel clutch 46h, apredetermined angle of rotation will be imparted to the cam 47.

' This angle can be adjusted by means of the slide 460 arranged in theadjusting head 46b, which slide can be shifted from the position shownin Fig. 12 toward the axis of rotation of the adjusting head 46b. In theposition of the slide 46c shown in Fig. 12, the maximum of rotation isimparted to the extension 46g race of the free wheel clutch 46h.

' In the diagram of the crank cycle (Fig. 13) a-b denotes the forwardstroke and b-a the return stroke of the crank, and c-d the portion ofits return stroke during which cam 46 actuates the extension 46g of theouter race of the free wheel clutch 46h. But, of course, the action ofcam 46 could occur in any other portion of the crank cycle except theportion during which cam 31 is actuating the feed roll means, andwhichcan take place near the dead position of the cycle as, for instance,either toward the end of the return stroke as denoted by e-f or at thebeginning of the forward stroke.

The hand wheels 30a, 30a, the worms 29, 29' (Figs. 2 and 3') serve atwofold purpose. On the one hand they are to protect the spindles 17,17' against rotation when the cylinder nuts are rotated for changing thegap, and on the other hand to accurately regulate the gap in its entirewidth.

The intermediate shaft 2 that drives the crankshaft 5 is coupled to amotor or other source of power. In Figure 2, the material worked on bythe roll segment 14 and counter-tool 16 is shown being fed by thefeeding rolls 37 and 37 I claim:

1. A stretching machine having in combination a reciprocating stretchingtool member and a counter-tool member mounted'in gap relation thereto, acrank shaft operatively connected to said stretching tool member, arotat able element mounted on said crank shaft having a camtrackthereon, a bell-crank having a roll member at one end thereof guided insaid cam-track and a head piece member linked to its other end andreciprocated thereby, a regulating spindle mounted in said head piece,said mounting causing said regulating spindle to reciprocate with saidhead piece and including means providing for regulating movement withrespect to said head piece, means actuated by said reciprocatingmovement for creating said regulating movement, a rack member actuatedbysaid spindle, and means actuated by movement of the rack member tomove the counter-tool member toward and away from the stretching toolmember.

' 2. 'A stretching machine having the structure set forth in claim 1 inwhich the means actuated by the rack member includes a shaft,- worm gearmeans mounted on the shaft, spindle means supporting the counter-toolmember, and cylinder nuts rotatable by the worm gear means and inengagement with the spindle means to raise or lower the same.

3. A stretching machine having a frame, a crankshaft mounted forrotation on said frame, a stretching toolmember reciprocated by therotation of said crankshaft, a counter-tool member mounted in gaprelation to said stretching tool-member, means for feeding metal to bereduced in thickness between said members, means for actuating the feedmeans in accordance with the reciprocation of the stretching member,said latter means including a cam on the crankshaft, a joint headmounted in proximity to said cam, a roller carried by said joint head, apush rod carried by said joint head, a free wheel clutch linked to thepush rod, a claw-coupling wheel coupling the free wheel; and means forgradually changing the rate of feed including an element rotatable withthe crankshaft, an adjusting head mounted in proximity to said element,a roller on said adjusting head, a slide movable on said adjusting head,a push rod pivoted to one end of the slide, means rotatably mounted onthe other end of the push rod comprising a lever-like exten-' of theouter sion of an outer'race of another free wheel clutch,- a cam securedto the inner ring of the last named free wheel clutch, a roll rotatablymounted in contact with the cam, and a push rod connecting the roll andthe first named free wheel clutch.

4. A stretching machine having a frame, a crankshaft mounted forrotation on said frame, a stretching toolmember reciprocated by therotation of said crankshaft, a counter-tool member mounted in gaprelation to said stretching tool-member, roll means for feeding metalbetween said members, means for actuating the roll means in accordancewith the rotation of the crankshaft, said latter means including a camon the crankshaft, a joint head mounted in proximity to said cam, aroller carried by the joint head, a push rod carried by the joint head,a free wheel clutch, means linking the free wheel clutch to the pushrod, a claw coupling engageable with the free wheel clutch, shaft meansconnected to the claw coupling, and means connecting the last namedshaft means with the roll means.

5. The stretching machine set forth in claim 4 having in combinationwith the feed roll means; means for introducing between the feed rollmeans the material to be fed to the stretching tool including levermeans, eccentric means rotatable by said lever means, means movable bythe eccentric means to lift the feed roll means; and means for providingfeed roll pressure necessary for feeding.

6. A stretching machine having a stretching tool member and acounter-tool member mounted in gap relation thereto, a crankshaftoperatively connected to said stretching tool member, feed roll meansfor feeding metal to be stretched by said members, means comprising acam rotatable with the crankshaft, means responsive to the motion of thecam member for actuating the feed roll means, additional means actuatedby the crankshaft for gradually changing the rate of feed, and othermeans actuated by the crankshaft controlling the motion of thecounter-tool member toward and away from the stretching tool member.

7. A stretching machine for reducing the wall thick ness of articles ofrectangular cross section comprising a frame, a slide member arrangedadjacent to and supported against said frame, a journal arrangedadjacent to and supported against said slide, a roll segment connectedwith said journal by lateral guide plates and supported on its entirelength against said journal, a crankshaft operatively connected withsaid slide member, a counter-tool having a feeding surface forming anangle with the stretching surface, said counter-tool being mounted ingap relation to said roll segment, feed roll means for feeding metal tobe stretchedbetween said roll segment and counter-tool, acam rotatablewith the crankshaft, means responsive to the motion of the cam foractuating the feed roll means, additional means actuated by thecrankshaft for changing the rate of feed, and

other means actuated by the crankshaft controlling the motion of thecounter-tool toward and away from the roll segment.

8. A stretching machine for reducing the wall thickness of articles ofrectangular cross section comprising a frame, a slide member suspendedon and supported against saidframe, a journal suspended on said frameand'supported against said slide member, a roll segment suspended bymeans of lateral guide plates on and supported on its entire lengthagainst said journal, a crankshaft operatively connected with saidslide, a counter-tool having a feeding. and a stretching surface theplane of the feeding surface forming an angle with the stretchingsurface, said counter-tool being mounted in gap relation with said rollsegment; feed roll means for feeding metal to be stretched between saidroll segment and counter-tool, a cam rotatable with the crankshaft,means responsive to the motion of the cam for actuating the feed rollmeans, additional means actuated by the crankshaft for changing therate'of feed, and other means actuated by the crankshaft controlling themotion of the counter-tool toward and away from the roll segment.

9. A stretching machine having in combination a stretching tool memberhaving a forward stroke and a return stroke, and a counter-tool membermounted in gap relation thereto; means for actuating said first toolmember, means for changing the gap in varying amounts including arotatable element having a cam-track thereon, means for rotating saidrotatable element, a bellcrank having a roll member at one end thereofguided in said cam-track and a head piece member linked to its other endand reciprocated thereby, a regulating spindle, means mounting saidregulating spindle in said head piece for reciprocating movement inunison therewith and for rotatable movement with respect thereto, meansactuated by said regulating spindle to move one of said tool members tochange the gap between the stretching tool member and the counter-toolmember, worm gear means operatively engaged to said regulating spindleto rotate the same, means operated by the rotation of said spindle tovary the extent of movement of said onemember, a'reg'ulating lever, andmeans coupling the regulating lever with the worm gear means forregulating the extent of movement of said one member.

References Cited in the file of this patent UNITED STATES PATENTS748,870 Jones Jan. 5, 1904 1,725,594 Montgomery Aug. 20, 1929 1,890,803Coe Dec. 13, 1932 2,153,839 Liebergeld Apr. 11, 1939 2,218,460 SingerOct. 15, 1940 FOREIGN PATENTS 720,076 Germany Apr. 23, 1942

